Trailer hitches including a hitch ball for connecting a towing vehicle to a trailer have long been known in the art. Examples of such are disclosed in a number of patents including, for example, U.S. Pat. No. 3,482,856 to Reese; U.S. Pat. No. 3,694,006 to Goode et al.; U.S. Pat. No. 3,768,837 to Reese; U.S. Pat. No. 4,033,601 to Lindahl et al. and U.S. Pat. No. 5,375,867 to Kass et al.
Most hitch balls are either directly mounted to a draw bar or a ball mount head carried on a hitch bar by means of a threaded mounting shank and cooperating locking nut or nut and lock washer. More specifically, the threaded mounting stem extends through an aperture in the draw bar/ball mount head and the locking nut or nut and locking washer are snugly tightened against the draw bar/ball mount head to secure the trailer hitch ball in position. While this provides a very adequate connection, many individuals are frustrated when the threaded mounting shank of the hitch ball rotates in the ball mount head when attempting to tighten the securing nut. When this occurs, it is not possible to complete the tightening operation unless tools are employed to prevent this from happening.
One way of addressing this problem is disclosed in U.S. Pat. No. 5,040,817 to Dunn. In Dunn, the pedestal or upper portion of the hitch ball mounting shank includes wrench flats that allow the ball to be held in position with a wrench during the nut tightening operation. While this is a functional solution to the problem, it must be appreciated that this involves the manipulation of two tools, one wrench to secure the hitch ball mounting shank from rotation and one wrench to tighten the securing nut. Many individuals find the manipulation of two tools inconvenient or difficult. Further, two appropriate tools are not always readily available to allow the connection to be made.
Another approach to address this problem is disclosed in co-pending U.S. patent application Ser. No. 08/575,417, filed Dec. 20, 1995, entitled "Trailer Hitch Receiver With Hitch Ball Lock", also assigned to the assignee of the present invention. This document discloses a trailer hitch receiver including a hitch bar, a ball mount head, a hitch ball with a threaded mounting stem or shank and a fastener for securing the hitch ball to the ball mount head. More specifically, the ball mount head includes a mounting aperture with a sidewall defining an acircular outline. The mounting shank of the hitch ball includes a locking element for engaging within the sidewall defining the acircular outline. As a result of this structural relationship, rotation of the hitch ball mounting shank relative to the ball mount head is prevented so that the fastener may be easily secured thereto and tightened to hold the hitch ball in position.
While such a trailer hitch receiver design is fully effective to allow simple and convenient hitch ball mounting, it should be appreciated that both the draw bar/ball mount head receiving the hitch ball and the hitch ball shank must be designed for cooperative engagement. Hence, this approach is not appropriate for retrofit and cannot be used to successfully address this problem on equipment already in the field.
Recognizing these and other shortcomings, a need is hereby identified for an improved structural arrangement whereby a mounting stem of a hitch ball may be secured against rotation relative to the draw bar/ball mount head during connection of the hitch ball thereto.